Preparation of arylenebenzoxazolols and arylenebenzothiazolols



PREPARATION or ARYLENEBENZOXAZOLOLS AND ARYLENEBENZOTHIAZOLOLS Fred Applegath and Raymond .A. Franz,

k., assignorstofiMonsanto Chemical Company, St. Louis,'M0.,- a corporation of Delaware NoDrawing." Application March is, 1957 ,Serial No. 646,577

-'8 Claims. (Cl. 260-304) The present invention rela es to ya new process for the production of azolest A Azoles can be prepared by reacting 2-hydroxy and'2- thiol substituted ,mono-primary-arylamines with carbonyl sulfide (COS).,-; Thisprocess, however, requires excep: tionally long reaction yields .of the desiredazole.

It is an object of this invention to provide, an

proved process for the production of azoles. It is a further objeet of: this invention =-to provide an improved process for the'production of .azoles from carbonyl sulfide and Z-hydroxy and 2-thiol substituted mono-primaryarylamines. Other objects will become apparent from the description of the invention. a,

Ithas now been 'discovered' thafa'z'oles can be pre pared "by reacting at 'an' elevated" temperature carbonyl sulfide and a compound selected from the group cdnsisting of Z-hydroxy substituted mono-primary-arylamines and 2-thiol substituted mono-primary arylamines in the presence of an alkaline catalyst having a dissociation constant greater than 1X10* The following examples illustrate this invention.

Example I mixture thus obtained is evaporated to near. dryness,

precipitating the desired product which is removed by filtration and washed with cold benzene. A good yield of Z-hydroxybenzthiazole is obtained.

Example II The procedure set forth in Example I is repeated using in place of the o-aminobenzenethiol 0.20 mol of o-amino' phenol. An excellent yield of 2-benzoxazolol is obtained.

Example III Procedure set forth in Example 1 is repeated using in place of o-aminobenzenethiol, 0.20 mol of fi-thiOl-OC- naphthylamine. An excellent yield of 2-hydroxy-flnaphthathiazole is obtained.

Example IV Procedure set forth in Example I is repeated using in place of o-aminobenzenethiol, 0.20 mol of a oz-thiOl-B- naphthylamine. An excellent yield of 2-hydroxy-a-naphthathiazole is obtained.

Example V The procedure set forth in Example I is repeated using in place of o-aminobenzenethiol, 0.20 mol B-hydroxy-anaphthylamine. An excellent yield of 2 hydroxy-finaphthoxazolol is obtained.

El Dorado,

periods to produceany practical 2,915,525 Patented Dec. 1, 1959 7 Example VI The procedure set forth in Example I is repeated using in place of o-aminobenzenethiol, 0.20 mol a-hydroxy-finaphthylamine. An excellent yield of 2 hydroxy-anaphthoxazolol is obtained.

Example VII The procedure set forth in Example I was repeated using in place of ,triethylamine 0.02 mol of sodium oleate. An excellent yield of 2-hydroxybenzthiazole is obtained.

Example VIII The procedure set forth in Example I is repeated using in place of triethylamine 0.02 mol of triethanolamine.

An excellent yield of Z-hydroxybenzthiazole is obtained.

Example IX The procedureset forth in Example I-is repeated using inplac'e of triethylamine 0.02 mol of potassium hydroxide. Y An excellent yield of Z-hydroxybenzthiazole is ob tained.

arylamine can be used in this process.

In each of the preceding examples the yields obtained are sig ificantly higher than yields obtained by the same process carried out in the absence of an alkaline catalyst.

AnY'Z-hydmxy or Z-thiol substituted mono-primary By mono-primaryaryla rnine is meant an aryl compound containing not more than one NH group attached; to an aromatic carbon atom. ,These amines may be further substituted with one or n'io re substituentgroupswhich are inert under 5 5; conditions of thereaction ie. 'do not prevent the formatioii of any of the desiredazoles. groups that can be present on the aryl radical are halo gens, including chlorine, bromine, fluorine and iodine, alkyl, alkoxy, aralkyl, dialkylamino, hydroxy, thiol, nitro, cyano, cyanoalkyl, cyanoalkoxy, etc. In the case of any of the alkyl substituents, alkyl groups containing from 1 to 18 carbon atoms are preferred. The mono-primaryarylamines can be monosubstituted or polysubstituted with one or more of the above mentioned groups.

The reaction temperature may also be substantially varied. Elevated temperatures are used. A temperature of at least 60 C. is preferred and temperatures as high as 200 C. can be employed. Temperatures in the range of from about 70 C. to about C. are particularly preferred.

While the reaction will take place at atmospheric pressure, elevated pressures are preferred. A reaction pressure varying from about 25 p.s.i.a. (pounds per square inch absolute) to about 250 p.s.i.a. is particularly advantageous. Reaction pressures as high as 500 p.s.i.a. or even higher can be used if desired but oifer no particular advantage.

The proportions of reactants used in this process are also subject to substantial variation. The mole ratio of carbonyl sulfide to the arylamine can be varied from about 0.5:1 to about 4:1.

If desired the process can be carried out in the presence of an inert solvent or diluent. For this purpose alkyl alcohols containing from 1 to 8 carbon atoms are preferred. Other diluents which can be employed in this reaction are hydrocarbons, halogenated hydrocarbons, mineral oils, ethers, amines, glycols and acid amides. Water per se is not a preferred diluent although it can be present in minor amounts in the organic diluent. The following are examples of materials that can be emisopropanol, isopropyl ether, ethanol, pyridine, isopropanol-water, ethylene glycol, methyl Cellosolve, tetrahydrofurfuryl alcohol, N,N-dimethylaniline, N,N-diethyl-ethanolamine, formamide, amyl alcohol, and benzene.

. Typical of substituent Any alkaline material having a dissociation constant greater than about l 10 can be used as the alkaline catalyst in this reaction. For this purpose tertiary alkyl amines containing from 1 t l8 carbon atoms are par ticularly preferred. Other catalysts that can be used are quaternary ammonium hydroxides, the alkali metal hydroxides, of which sodium hydroxide and potassium hydroxide are particular examples, alkaline alkali metal salts, such as sodium oleate, N,N-dirnethylbenzylamine, N,N-diethyl-p-toluidine, tri-nhexylamine, triethanolamine, N,N-diethyloctadecylamine, a mixture of magnesium oxide and methanol, and a mix ture of calcium and methanol. The quantity of alkaline material used for the catalyst can also be varied substantially. Minor amounts are preferred. From about 0.002 to about 0.2 mole of the alkaline catalyst per mole of the arylamine has been found to be particularly useful.

After the reaction is complete the azole can be recov* ered from the reaction mixture by any method well-known to those skilled in the art.

What is claimed is:

1. A process for preparing azoles which comprises reacting by mixing at an elevated temperature and a pressure of at least 25 p.s.i.a. carbonyl sulfide and a compound selected from the group consisting of 2-hy droxy substituted mono-primary arylamines and 2-thio1 substituted mono-primary arylamines in the presence of an alkaline catalyst having a dissociation constant greater than 1X 2. A process as described in claim 1 wherein the reaction is carried out at a temperature in the range of from about 70 C. to about 150 C.

3. A process as described in claim 2 wherein the reac- I tion is carried out in an inert diluent.

4. A process as described in claim 3 wherein thealkaline catalyst is a tertiary amine.

hydroxides, alkaline earth metal prises reacting by constant greater than about 1 10- p of at least 25 p.s.i.a. in the presence having a dissociation constant greater than about 1X 10- at least p.s.i.a. in the presence 7. A process for preparing Z-hydroXy-a-naphthathiazole which comprises reacting by' mixing a-thiol-B-naphthylamine and carbonyl sulfide at a temperature in the range of from about C. to about C. and a pressure of a tertiary amine 8. A process for preparing 2-hydroxy-fl-naphthathiazole which comprises reacting by mixing fl-thiol-wnaphthylamine and carbonyl sulfide at a temperature in the range of from about 70 C. to about 150 C. and a pressure of of a tertiary amine having a dissociation constant greater than about OTHER REFERENCES -Hogelloch: Chem. Abstracts, vol. 44', col. 9937-8 

1. A PROCESS FOR PREPARING AZOLES WHICH COMPRISES REACTING BY MIXING AT AN ELEVATED TEMPERATURE AND A PRESSURE OF AT LEAST 25 P.S.I.A. CARBONYL SULFIDE AND A COMPOUND SELECTED FROM THE GROUP CONSISTING OF 2-HYDROXY SUBSTITUTED MONO-PRIMARY ARYLAMINES AND 2-THIOL SUBSTITUTED MONO-PRIMARY ARYLAMINES IN THE PRESENCE OF AN ALKALINE CATALYST HAVING A DISSOCIATION CONSTANT GREATER THAN 1X10-10. 